Adaptation to a temperate climate was a prerequisite for the spread of maize across a broad geographical range on the earth. To explicitly explore the demographic process underlying maize adaptation, we remodeled the differentiation event between temperate and tropical populations using a diffusion-based method with Non-Stiff Stalk group as a proxy for temperate maize. Using multiple sequential Markovian coalescent (MSMC) approaches, we estimate the split time of tropical and temperate maize around 3000 to 5000 years ago, and the population size underwent shrink after the split. The composite likelihood approach elaborates a distinct tropical-temperate divergence event that initiated  4958 years ago (95% confidence interval (CI): 4877- 5039 ), from an ancestral population whose effective size was  24,162 (95% CI: 23,914-24,409). We detected continuous gene flow between tropical and temperate maize accompanied the differentiation of temperate maize. Long identical-by-descent (IBD) tracks shared by tropical and temperate inbred lines have been identified, which might be due to the gene flow between tropical and temperate maize, or artificial selection during domestication and crop improvement. Understanding the demographic history of maize diffusion not only provides evidence for population dynamics of maize, but also, will assist the identification of regions under selection and the genetic basis of complex traits of agronomic importance.